MICROANATOMY

Detailed explanation-1: -A target cell responds to a hormone because it bears receptors for the hormone. In other words, a particular cell is a target cell for a hormone if it contains functional receptors for that hormone, and cells which do not have such a receptor cannot be influenced directly by that hormone.

Detailed explanation-2: -All classes of hormones elicit the majority of their physiological effects via specific receptors which are located in three separate compartments of target cells: cell membranes (peptide and glycopeptide hormones), cytoplasm (steroid hormones) and nucleus (thyroid and steroid hormones).

Detailed explanation-3: -Once hormones find a target cell, they bind with specific protein receptors inside or on the surface of the cell and specifically change the cell’s activities. The protein receptor reads the hormone’s message and carries out the instructions by either influencing gene expression or altering cellular protein activity.

Detailed explanation-4: -Hormone receptors which are present inside the target cells are called intracellular receptors.